Assessment of Ni/Pd/Au–Pd and Ni/Pd/Au–Ag Preplated Leadframe Packages Subject to Electrochemical Migration and Mixed Flowing Gas Tests

Preplated leadframes packages with a new noble metal finish type were exposed to various electrochemical migration tests, and mixed flowing gas environments to assess the quality and reliability due to these environmental conditions. Packages were tested as discrete parts and also as parts mounted onto printed circuit boards to assess the effect of reflow soldering. Selected packages with SnPb plated leadframes were tested for comparison purposes. After test exposure, optical microscopy, scanning electron microscope, and energy dispersive spectroscopy analyses were conducted to evaluate the corrosion behavior. Corrosion and creep corrosion on the leads were observed on all the preplated test samples subject to the mixed flowing gas. Creep corrosion over the mold compound surface was identified on the unmounted quad flat no-lead packages. The creep corrosion products were found to be electrically conductive and could bridge adjacent lead pairs